Overhead line vertical galloping on bundle configurations: stability criterion and amplitude prediction

The authors discuss a study which relies on a simulation program for the first three eigen modes of the vertical and torsional movements in a parametric approach to the phenomenon of galloping. Their aim is to discover the specific relations connecting the structural parameters of the lines liable to galloping. The determining factor is shown to be the torsion of the conductors. Three essential aspects are discussed: the use of four dimensionless parameters; a parametric study of the stability; and an original approach to the analytical predetermination of the maximum amplitudes. The critical range of the wind speed favourable to galloping is given. The calculations are made on the basis of the aerodynamic curves produced by various laboratories for ice coatings observed in the field. Finally the authors examine the effect of some anti-galloping devices (pendulums)